Pump



Feb. 3, 1942. s PARD'EE rum? Filed July 51, 1940 2 Sheets-Sheet 1 Feb.3, 1942. H. s. PARDEE PUMP Filed July 31, 1940 2 Sheets-Sheet 2 Patented1 .1.3. 1942' ,UNITED STATESFPATENT OFFICE Applica i o z 1Ei :STl;, S eri:l 1 V: 348,G42

20 Claims.

This invention relates to pumps, and with regard to certain morespecific features, to highpressure, hydraulic pumps.

Among the several objects of the invention may be noted the provision-ofa reliable highpressure, hydraulic pump, particularly (though notnecessarily exclusively) for low-volume operations, which hasthesimplicity of a rotary pump but does not require its complications suchas a vacuum or suction shaft seal; the provision of a pump of this classwhich is designed particularly for high velocities with high mechanicaland volumetric efliciency and which will handle dirty pumpage ifnecessary; and the provision of apparatus of this class which is simpleand compact. Other objects will be in part obvious and in part pointedout hereinafter.

The invention accordingly comprises the elements and combinations ofelements, features of construction, and arrangements of parts which willbe exemplified in the structures hereinafter described, and the scope ofthe application of which will be indicated in the following claims.

In the accompanying drawings, in which is illustrated one of variouspossible embodiments of the invention,

Fig. 1 is a side elevation;

4 Fig. 2 is a right-end elevation of Fig. 1;

Fig. 3 is a vertical section taken on line 3-3 of Fig. 1;

Fig. 4 is a vertical section taken on'line 4--4 of Fig. 1 but enlarged;

- Fig. 5 is a longitudinal section taken on line 55 of Fig. 4;

Fig. 6 is a perspective view of a pump plunger and its separated drivingslipper; and,

Fig. 7 is a perspective view-of a plunger returnspring, on a reducedscale.

.Similar reference characters indicate corresponding parts throughoutthe several views of the drawings.

Referring now more particularly to Fig. 1, there is shown at numeral I apump casing or body which, by means of studs I (see also Fig. 5), isattached to the adaptor 3 of a motor casing 5. The adaptor 3 of themotor casing 5 is held by means of studs 9.

The adaptor 3 of the motor casing 5 forms the support for a bearing II,in which rotates the drive shaft I 3 for the present pump. The

driv shaft 13 may be operated from any suitable source, such as by ashaft of an electric motor, aeroplane engine, or the like, dependingupon the application to which the present pump is put. Application topressure-control systems is an exemplary use of the vention.

The bearing II is sealed as shown at l5. At I1 is shown an enclosinghead which is bolted present into the body I to form, with the seal IS,a sealed enclosure for the driving parts. The seal here referred to isnot the avoided seal specified in the above objects. The latter is thevacuum shaft seal necessary in rotary vane and centrifugal machineswhich are subject to the suction pressure. The pressure carried withinI, 3 and I1 is normally atmospheric. Splash lubrication is used, as willappear.

The driving parts include a circular eccentric I 9 keyed to an extension2'! on said shaft I3. Borne on the eccentric l9 by means of needlebearings 23 is a cylindric sleeve 25. The needle bearings are held fromendwise escape by washer plates 29.

Bearing on the outer periphery of the sleeve are four crescent-shapedslippers 21. One slipper is as shown in Fig. 6 and comprises an outercylindrical bearing 29 and endwise walls or flanges 3| with comerrecesses 32 and chamfers at 34. The circular bearing 29 is for thepurpose of fitting the circularly formed end 33 the plunger 35, to serveas lateral holding guides. The bottom of each slipper is curved as shownat 31, the radius of curvature being equal to the radius of the sleeve25.

In operation, there is some sliding motion forward and. backward duringeach revolution, between the slipper 21 and the sleeve .25, due to thevarying angular distances caused by the different eccentric positions.

Each plunger 35 slides in a sleeve 39. The sleeves are pressed intosuitable openings in the body I, as shown in Figs. 4 and 5.

. Each sleeve 39 is open at its outer end and is machined flat with anoptical fiat at 4|. Each sleeve is also open at its inner end to permitof extending the respective plunger to its slipper 21. Each sleeve isalso provided with inlets 43 within a recess 45. This recess 45registers with The recess 41 communicates with and formspart' of thesuction chamber 49 which is cored into the-body l in an inner peripheralform. This suction chamber 49 is in communication with the suction inletshown to the right at 5| (Fig. 4). As indicated, the upper edges of theinlets 43 in the sleeves 39 are straight (see numeral 53).

Normally seating on each machined optical tions between said plungers.

flat d! is a valve cup 55 which is normally biased to its seat by meansof a spring 55. The inner ends of the cups 55 are also optical flats.Each spring 5! reacts from an enclosing cap 59 which is threaded intothe opening through which the respective sleeve 39 is applied forforce-fitting into the respective more or less radial opening M.

The outer peripheral exhaust or outlet chamber 63 of the pump is coredout circularly around, and spaced from, the inlet passage t9 and is incommunication with the open ends of the sleeves 39 when the valves 55are lifted.

The stroke of each plunger 35 in each sleeve 39 is such that the end 62thereof moves from a point within the outer edge of the openings 43, todirect contact (if'necessary) with the bottom of the valve 55. As aplunger contacts its valve 55 (when this occurs)", there is anadditional slight movement of the order of about .005, or just enough totake up all clearance, and to give the pump a slight negative clearance.This is for the purpose of assuring that all of the conyielding forcewhich will accommodate itself to the small change in distance betweenthe holes in opposite plungers.

As will beseen by examination of Fig. 4, the center lines of oppositesleeves 39 and plungers 35 are not co-axial, although parallel, and areoffset on opposite sides of the center of shaft 2|.

The oifset is in a direction so that the driving 'thrust through thecenter of the eccentric will on an average more nearly be directed alongthe center line of each plunger 35 upon the compression stroke, than onthe suction stroke. This means that the respective slipper 21 is leastangled with respect to its plunger 35 upon the tents of each sleeve 39will be emptied upon each compression stroke, including any air or gaswhich might otherwise re-expand upon the suction stroke. All fluidpumped into and through the outlet chamber 63 is ultimately forced tothe pump outlet shown at numeral 65. Ordinarily, the liquid forced outby the plunger 35, unseats the valve cup 55 but should a slug of air orthe like he encountered this is positively completely forced out by thecontact of the plunger 35 with the valve cup. No re expansion of any airin a clearance space is possible because there is no clearance space.

Each sleeve 39 is slotted, as indicated at 61'. At a position adjacentthe respective slot 61, each plunger 35 carries an opening 63 which isdrilled at a slight angle with respect to the axis of the plunger. Thisis for the purpose of receiving and holding a hook end H of an arcuateor bowed spring 12 (see Fig. 7).

Each spring 1'2 has its hook-shaped 'ends H placed in openings 69 ofoppositely located plungers 35. It is clear from Fig. 5 that theeffective lengths of the hooks of one pair of springs l2are greater thanthe effective lengths of the hooks of the other pair, so that thearcuate portions of these springs may lie in difierent planes. Eachspring 12 is so formed that in placing it as above described, the hooksll need to be spread somewhat so as to cause the oppositely locatedplungers to be drawn toward one another. Hence they bear upon theirrespective slippers 21, which in' turn bear upon the sleeve 25. Thuseach slipper is pressure-confined. The springs 12 are in moderatetension at the closest relationship between opposite plungers. The bowof each spring lies radially outside the orbit of the sleeve 25.

An advantage of having the spring connector 12 carried betweenoppositely located moving plungers 35 is that the spring connectors thusmove back and forth with the plungers, while at the same timethey'respond to any relative mo- Since oppositely located plungers arealways moving in parallel directions at nearly the same rates, theirrelative motion is slight, this means that the spring deflections formaintaining the slight differences in position clue to relative motionsare small and much less than the stroke of each plunger. Thus the forceholding each plunger and slipper biased compression stroke, and mostangled upon the relatively light suction stroke when drawn back by therespective spring 5! (compare oppositely located slippers in Fig. 4). Byleast. angled here is meant the least angle with respect to a conditionof symmetry between slipper and plunger.

Operation is as follows:

Rotation of the eccentric l9 causes oscillation of the sleeve 25. Thisoscillation of sleeve 25 does not necessarily mean that it rotates withrespect to the frame of the machine. When any plunger is in a positionnearest the center, its inner end is closer to the inner end of anadjacent plunger and likewise when the plunger is furthest out theangular distance between the inner end of this plunger and the innerends of its adjacent plunger is a maximum. Thus the slippers constantlymove toward and away from each other, sliding on the periphery of thesleeve. The slipper provides a surface contact instead of a line contactbetween the plunger and sleeve. This makes possible film lubrication andminimizes wear and frictional losses.

As the sleeve 25 oscillates, the slippers 21' are reciprocated alonglines parallel to radial lines and at the same time they are oscillatedwith respect to the plungers 35', which are reciprocated Upon itssuction stroke each plunger is drawn back by the driving movement of theopposite plunger (through.

the spring 12 acting as a drag link). This draws in fluid from thechamber 49 and upon a compression stroke forces fluid out past therespective valve into the outlet chamber 63 and to the .outlet 65. i

Each plunger 35 is sprung down against its slipper 21, and each slipper21 is sprung down against its sleeve 25 by means of the action of therespective spring 12 engaging the opposite plunger. This is in additionto the drag above mentioned. It may be-remarked that the oppositeopenings 69 do not retain a constant separated distance during thecyclic action of the eccentric [9. The variation, due to the geometry ofthe apparatus, is compensated for by the resiliency of the respectivespring 12 which spans the respective pair of openings 69. It will beunderstood, although the pump shown is a fourcylinder arrangement, thatother multiples pref erably even) may be used.

Although the eccentric I9 is located in a sealed chamber and runs inlubricant which may be supplied through a cup 15 and removed forreplenishment from a cup 11; nevertheless, nohighpressure packing isemployed. The lower ends of the plungers 35 require no packing becauseof the lap fits.

A favorable field of usefulness for the device is in small capacities athigh pressures. A pump made according to the disclosure herein hasoperated at 6000 R, P. M. with little loss of volumetric efllciency.Another has operated at 3500 R. P. M. at a liquid pressure of 4000pounds per 4 square inch with a volumetric efficiency of practically100% and a mechanical efllciency of about, 92%. Another operates at 5000R. P. M. at 3000 pounds per square inch.

In view of the above, it will be seen that \the several objects of theinvention are achieved and other advantageous results attained.v

As many changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

I claim: e

1. A pump comprising a cylinder, a reciprocating plunger in thecylinder, rotary eccentric means, a rotary sleeve on the eccentric meansand a slipper between the plunger and the sleeve on the eccentric'means,said slipper having a contact surface with the plunger constituting apartial cylinder, and another contact surface with the sleeveconstituting another partial cyllinder. v

2. A pump comprising opposite cylinders, reciprocating plungers in thecylinders, rotary eccentric means between the cylinders, a rotary sleeveon the eccentric means, slippers between the respective plungers and thesleeve on the eccentric means, each slipper having a contact surfacewith its respective plunger. constituting a partial cylinder, andanother contact surface with the sleeve which constitutes anotherpartial cylinder, and spring means carried by the plungers and biasingthem toward one'another while moving with them.

3. A pump comprising a cylinder, 9. reciprocating plunger in thecylinder, an eccentric, a sleeve in which the eccentric rotates, and aslipper between the plunger and the sleeve, said slipper having anarcuate contact surface with the plunger, and another arcuate contactsurface with the sleeve. v

4. A pump comprising a cylinder, a reciprocating plunger in thecylinder, an eccentric, a sleeve n the eccentric, and a slipper betweenthe plunger and the sleeve, said slipper having an arcuate contactsurface with the plunger, and another arcuate contact surface with thesleeve, the axial center line of the plunger being offset withrespect tothe center of rotation of said eccentric in a direction such that theline of thrust is at a minimum average angle with respect to the plungerupon a compression stroke.

5. A pump comprising rotary eccentric means, plungers located onopposite sides of the eccen'- tric means, said eccentric meansreciprocating the plungers, spring means reacting between the plungersand moving with them to bia said plungers against the eccentric, saidspring means comprising an arched spring carried between plungers andclearing the eccentric in the plane of its movements. and sleeves inwhich the plungers reciprocate, said sleeves having guide slotscooperating with the springto maintain said spring in a predeterminedplane.

6. A pump comprising rotary eccentric means,

plungers which are not co-axial located on opposite sides of theeccentric means, spring means reacting between the plungers normally toforce them against the eccentric means, and

slippers rotary with respect to the plungers and forming bearings.therefor, said slippers having arcuate bearing surfaces on the eccentricmeans. 7. A pump comprising rotary eccentric means, plungers which arenot co-axial located on opposite sides of the eccentric means, springmeans reacting between the plungers normally to force them toward andagainst the eccentric means, and slippers rotary with respect to theplungers and forming bearings therefor, said slippers having arcuatebearing surfaces on the eccentric means, said spring-biasing meanscomprising an arched wire having attachments to the plungers.

8. A pump comprising eccentric means, a reciprocating plunger, and acrescent-shaped slipper between the eccentric means and the plungerhaving a concave arcuate surface contacting the eccentric means and aconvex arcuate surface contacting the plunger. 9. A pump comprisingeccentric means, a reciprocating plunger, and a crescent-shaped slipperbetween the eccentric means and the plunger having a concave arcuatesurface contacting the eccentric means and a convex arcuate surfacecontacting the plunger, the rotary axis of the eccentric means beingoutside the pressure axis of said plunger.

10. A pump comprising eccentric means, a

the suction chamber and having inlets communieating therewith, saidcylinders having outlets in the outlet chamber, check valves biased toseat over the outlets, radial plungers having ends moving from radialpositions within the inlet to force fluid from the outlets, said bodyportion having an open center, and said cylinders having outlets in saidcenter, operating means within said open center, said operating meanscomprising an eccentric, a sleeve around said eccentric and having abearing thereon, plungers in said cylinders, slippers between the sleeveand the plungers, said slippers'having oscillating contact with theplungers and a to-and-fro relative angular movement, and spring-biasingmeans between opposite plungers and movable therewith and shaped toclear the eccentric driving means. 12. A pump comprising at least twoopposed cylinders, a reciprocating plunger in each cylinder, eccentricactuating means interposed between saidplungers and reacting in thrustagainst the plungers to force them through their displacement strokes,the plungers being approximately radial with respect to the operatingperiphery of the eccentric means and substan tially in its plane ofrotation, yielding connecting-means between said plungers comprising anarched spring which clears the eccentric means in all positions of thelatter, said connecting means being mounted under suificient initialstress to ensure that each plunger will be drawn through its suctionstroke by the other plunger without substantial lost motion between theplunger so drawn and said eccentric means.

.13. A pump comprising a pair of cylinders, said cylinders havinglateral inlet ports formed in their walls, reciprocating plungersrespective- 1y inthe cylinders controlling said inlet ports, eccentricmeans interposed between said plungers and serving to actuate themalternately in thrust on their discharge strokes, the plungers beingapproximately radial with respect to the operating periphery of theeccentric means and substantially in its plane of rotation, the partsbeing so dimensioned that the plungers open the inlet ports at theinnermost end of their'strokes,

and a yielding connection between said opposed plungers comprising anarched spring which clears the eccentric means in all positions of thelatter, said connection being of sufficient strength and mounted undersufficient initial stress to cause each plunger to draw the otherthrough its suction stroke without substantial lost motion between theplunger so drawn and said eccentric means.

14. In a pump, the combination of a rotary shaft carrying an eccentric,asleeve rotatably mounted on said eccentric, a pair of opposedcylinders, said cylinders having slots in their proximate ends, aplunger working in each cylinder, each plunger having a spring seatwhich aligns with the slot in its cylinder, and a cylindricalslipper-seat in the end of the plunger, slippers, one for each plunger,each having a convex cylindrical journal surface which works in theslipper-seat of the corresponding plnn-ger' and a concave cylindricalbearing surface which engages said sleeve, means limiting movement ofeach slipper transverse to its plunger and paral lel with the axis ofthe sleeve, and an arcuate spring having hooked end portions whichproject from the plane of such are and extend through the slots inrespective'cylinders into engagement with the springv seats ofrespective plungers, said spring being sufiiciently stressed in tensionto maintain the plungers, slippers and sleeve in coactive thrustengagement.

15. The combination defined in claim 14 in -which thespring is so bowedthat it lies radially '17. The combination defined in claim 14 in whichinlet ports are formed in the cylinder yielding, while such inlet portis closed off bythe plunger.

'18. In a pump, the combination of a rotary shaft carrying an eccentric,a sleeve rotatably mounted on said eccentric, a pair of approximatelyradially opposed cylinders mounted with their axes parallel but offsetin opposite directions from the axis of said shaft, said cylindershaving slots at their proximate ends, a plunger working in eachcylinder, each' plunger having a spring seat which aligns with the slotin its cylinder, and a cylindrical slipper-seat in the end of theplunger, slippers, one for each plunger, each having a convexcylindrical journal surface which works in the slipper-seat of the corresponding plunger and a concave cylindrical bearing surface whichengages said sleeve, means limiting movement of each slipper transverseto its plunger and parallel with the axis of the sleeve, and an arcuatespring having hooked end portions which project from the plane of suchare and extend through the slots in respective cylinders into engagementwith the spring seats of respective plungers, the spring beingsufflciently stressed in tension to maintain the plungers,

slippers and sleeve in coactive thrust engagement.

19. In a pump comprising a frame forming a housing, a supporting bearingin one side of said housing, an eccentric having a rotary mounting insaid bearing and overhanging within the housing, radial cylinders in thehousing, plungers in the cylinders, removable means at the ends of saidcylinders permitting radial removal of the plungers through thecylinders, bearing means between the plungers and the eccentric, andspring means vyieldingly connecting opposite plungers to force themtoward one another and the eccentric, said spring means being located onthe overhung side of the eccentric opposite its rotary bearing, and aremovable cover on said housing opposite the overhanging eccentric,whereby upon removing the cover said springs are exposed for disassemblywithout disturbing the eccentric, and whereby said plungers and bearingmeans may be removed without disturbing said eccentric.

20. In a pump, a housing, a supporting hearing in one side of saidhousing, an eccentric having a'rotary mounting in said bearing andoverhanging within the housing, radial cylinders in the housingsubstantially in the plane of the cocentric, plungers in the cylinders,removable heads at the ends of said cylinders permitting radial removalof the plungers through the cylinders', pressure-confined bearing meansbetween the plungers and the eccentric, and spring means yieldinglyconnecting opposite plungers to force them toward one another and theeccentric to effect said confinement, said spring means being located onthe overhung side of the eccentric opposite its rotary bearing, saidbearing means being separable from the plungers and the eccentric simplyby removing the plungers and being held in place by said spring, and aremovable cover on said housing opposite the overhanging eccentric,whereby upon removing the cover said springs and said plungers andbearing means may be removed without disturbing said eccentric.

HARVEY S, PARDEE.

